It's on two rows like that because each row represents what will show up on the front of the bus at any one time, so it flashes back and forth between the two rows.
This is notable because buses have been saying less and less in recent years. They used to be quite descriptive. For example, if you caught it at the right time of day, the 220 might have said
which was all well and good if you were contemplating it from the platform at Central, but, considering it takes each row about three seconds to come and go, if you caught it somewhere far-flung on Highland Drive, you might never know where the bus you were getting on was going.
Unless, of course, you already knew everything about the 220. Hahaha . . .